An embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure

Abstract

The present invention provides an embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure. The embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure comprises N embedded reinforced unit cells, each comprising a concave hexagonal unit cell structure and a sinusoidal structure embedded within the concave hexagonal unit cell structure. The embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure is formed by a periodic array of the embedded reinforced unit cells. The present invention effectively improves the compression stability, self-contact effect, specific energy absorption, and energy absorption efficiency of the negative Poisson's ratio honeycomb lattice structure, exhibiting excellent performance.

Description

Technical Field

[0001] The invention relates to the technical field of engineering structures, and in particular to an embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure. Background Art

[0002] Poisson's ratio is one of the most important indicators of the elastic properties of solid structures and is defined as the negative ratio of transverse strain to longitudinal strain. Negative Poisson's ratio materials / structures, which contract laterally when compressed and expand when stretched, have attracted significant attention over the past 30 years since Lakes published his groundbreaking research in 1987. By utilizing the unique deformation properties of negative Poisson's ratio structures, the mechanical properties of some materials, such as plane strain fracture resistance, shear modulus, indentation resistance, fracture toughness, and acoustic properties, particularly energy absorption capacity, can be significantly improved. Furthermore, negative Poisson's ratio structures exhibit high energy absorption and dissipation and impact resistance, offering advantages in protective engineering. Existing negative Poisson's ratio materials / structures can be categorized, depending on their geometry and parent material, as negative Poisson's ratio foams, negative Poisson's ratio yarns, negative Poisson's ratio laminates, negative Poisson's ratio origami, negative Poisson's ratio lattices, and negative Poisson's ratio honeycombs.

[0003] Currently, researchers have studied and designed a variety of negative Poisson's ratio honeycomb structures, such as concave hexagonal honeycombs, star-shaped honeycombs, double-arrow honeycombs, and chiral honeycombs. The two-dimensional concave hexagonal honeycomb lattice structure has become the most widely studied negative Poisson's ratio structure due to its simple structure and wide range of applications.

[0004] However, traditional indented hexagonal honeycomb lattice structures face challenges such as compression instability and low stiffness, making them unsuitable for large deformations and preventing them from fully realizing their impact energy absorption potential. On the one hand, when compressed, the structure shrinks laterally, causing the material to aggregate toward the loaded area, increasing its instantaneous density and improving its load-bearing capacity and energy absorption characteristics. On the other hand, the structure often achieves auxetic expansion through bending or rotational deformation of the struts, which in turn weakens the structure's load-bearing capacity. In recent years, numerous novel honeycomb structures have been designed to simultaneously improve structural stiffness, strength, and energy absorption. For example, sinusoidal ribs, diamond ribs, and vertical ribs have been embedded in traditional two-dimensional indented hexagonal honeycomb structures to enhance overall mechanical properties. By embedding both horizontal and vertical ribs within a two-dimensional indented hexagonal unit cell, a bidirectionally reinforced structure can be achieved. However, according to Maxwell's criterion, this structure undergoes a transition from bending-dominated to tension-dominated deformation, resulting in a sudden drop in stress during compression, hindering compression energy absorption. Furthermore, it hinders contraction under compression, reducing shear resistance. Therefore, the existing two-dimensional concave hexagonal honeycomb lattice structure has problems of compression instability, low stiffness, low energy absorption characteristics and poor stability. Summary of the Invention

[0005] The present invention provides an embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure, which aims to solve the problems of compression instability, low stiffness, low energy absorption characteristics and poor stability of the existing two-dimensional concave hexagonal honeycomb lattice structure.

[0006] An embodiment of the present invention provides an embedded reinforced impact energy absorbing honeycomb lattice structure with a negative Poisson's ratio, wherein the embedded reinforced impact energy absorbing honeycomb lattice structure includes N embedded reinforced unit cell structures, wherein the embedded reinforced unit cell structure includes a concave hexagonal unit cell structure and a sinusoidal structure, wherein the sinusoidal structure is embedded in the concave hexagonal unit cell structure, and the embedded reinforced impact energy absorbing honeycomb lattice structure with a negative Poisson's ratio is formed by a periodic array of the embedded reinforced unit cell structures.

[0007] Preferably, the embedded reinforced unit cell structure includes a plurality of embedded reinforced unit cell structures, and the plurality of embedded reinforced unit cell structures are connected to each other by sharing the rods of the embedded reinforced unit cell structure.

[0008] Preferably, the embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure is composed of any m×n embedded reinforced unit cell structures; wherein m and n are both positive integers.

[0009] Preferably, the parameters of the concave hexagonal unit cell structure include the thickness t of the rod, the distance h1 of the concave position in the x-axis direction, the length h2 in the y-axis direction, the height b in the z-axis direction, and the angle θ1;

[0010] The equation of the sinusoidal structure is: y=Asin(2Πx / h1) in the x-axis direction, x=Asin(2Πy / h2) in the y-axis direction, where the sinusoidal amplitude parameter is A.

[0011] Preferably, A=1.

[0012] Preferably, A=3.

[0013] Preferably, A=5.

[0014] Compared with the prior art, the present invention has the beneficial effect of demonstrating an embedded, reinforced, impact-absorbing, negative Poisson's ratio honeycomb lattice structure comprising N embedded, reinforced unit cells, each comprising a concave hexagonal unit cell structure and a sinusoidal structure embedded within the concave hexagonal unit cell structure. The embedded, reinforced, impact-absorbing, negative Poisson's ratio honeycomb lattice structure is formed by a periodic array of these embedded, reinforced unit cells. This allows for stable compression deformation and negative Poisson's ratio effects over a wide deformation range, a significant self-contact enhancement effect, high specific energy absorption and energy absorption efficiency, and the ability to achieve a variety of adjustable stress-strain curves. Due to the excellent properties of the present invention, it exhibits significant potential for application in protective engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be described in detail below with reference to the accompanying drawings. The above and other aspects of the present invention will become clearer and easier to understand through the detailed description made with reference to the following drawings. In the accompanying drawings:

[0016] Figure 1 1 is a schematic structural diagram of an embedded enhanced unit cell provided by an embodiment of the present invention;

[0017] Figure 2 Schematic diagram of an embedded enhanced impact energy absorbing negative Poisson's ratio honeycomb lattice structure provided by an embodiment of the present invention;

[0018] Figure 3 yes Figure 1 Schematic diagram of structural parameters;

[0019] Figure 4 1 is a diagram showing compression test results of three sinusoidal amplitude parameters A provided by an embodiment of the present invention;

[0020] Figure 5 1 is a stress-strain curve diagram of three honeycomb lattice structures provided by an embodiment of the present invention;

[0021] Figure 6 Specific energy absorption curves of three honeycomb lattice structures provided by embodiments of the present invention;

[0022] Figure 7 1 is an energy absorption efficiency curve diagram of three honeycomb lattice structures provided by an embodiment of the present invention.

[0023] Among them, 11. Concave hexagonal unit cell structure; 12. Sinusoidal structure; 13. Embedded enhanced unit cell structure. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] Combined with attachment Figure 1-Figure 7 As shown, an embodiment of the present invention provides an embedded reinforced impact energy absorbing honeycomb lattice structure with a negative Poisson's ratio, wherein the embedded reinforced impact energy absorbing honeycomb lattice structure with a negative Poisson's ratio includes N embedded reinforced unit cell structures 13, wherein the embedded reinforced unit cell structure 13 includes a concave hexagonal unit cell structure 11 and a sinusoidal structure 12, wherein the sinusoidal structure 12 is embedded in the concave hexagonal unit cell structure 11, and the embedded reinforced impact energy absorbing honeycomb lattice structure with a negative Poisson's ratio is formed by a periodic array of the embedded reinforced unit cell structures 13.

[0026] Specifically, by embedding the sinusoidal structure 12 within the concave hexagonal unit cell structure 11, the embedded reinforced impact energy absorption negative Poisson's ratio honeycomb lattice structure is formed via a periodic array of the embedded reinforced unit cell structure 13. This allows for stable compression deformation and a negative Poisson's ratio effect over a wide deformation range; exhibits a significant self-contact enhancement effect; achieves high specific energy absorption and energy absorption efficiency; and enables the realization of a variety of adjustable stress-strain curves. Due to the excellent properties of the present invention, it exhibits significant application potential in protective engineering.

[0027] In this embodiment, the embedded reinforced unit cell structure 13 includes a plurality of embedded reinforced unit cell structures 13 , and the plurality of embedded reinforced unit cell structures 13 are connected to each other by sharing the rods of the embedded reinforced unit cell structure 13 .

[0028] In this embodiment, the embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure is composed of any m×n embedded reinforced unit cell structures, where m and n are both positive integers. The embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure in this embodiment is composed of 3×5 embedded reinforced unit cell structures 13.

[0029] In this embodiment, the parameters of the concave hexagonal unit cell structure 11 include the thickness t of the rod, the distance h1 of the concave position in the x-axis direction, the length h2 in the y-axis direction, the height b in the z-axis direction, and the angle θ1;

[0030] The equation for the sinusoidal structure 12 is: y = Asin(2Πx / h1) along the x-axis, x = Asin(2Πy / h2) along the y-axis, where the sinusoidal amplitude parameter is A. Compared to the traditional concave hexagonal unit cell structure 11, this new sinusoidal amplitude parameter A is added. By adjusting this sinusoidal amplitude parameter A, the mechanical properties and energy absorption characteristics of the embedded, enhanced impact energy absorption, negative Poisson's ratio honeycomb lattice structure of the present invention can be adjusted over a wide range.

[0031] Preferably, A=1.

[0032] Preferably, A=3.

[0033] Preferably, A=5.

[0034] In this embodiment, in order to illustrate the significant advantages of the embedded reinforced impact energy absorption negative Poisson's ratio honeycomb lattice structure, the present invention performs finite element simulation on three types of honeycomb lattice structures from three perspectives, including compression stability test, stress-strain test, and specific energy absorption and energy absorption efficiency test.

[0035] Each honeycomb lattice structure is composed of 3×5 unit cells. The three types of honeycomb lattice structures are embedded reinforced impact energy absorption negative Poisson's ratio honeycomb lattice structure with different sine amplitude parameters A, concave hexagonal honeycomb lattice structure (NAH_T) and concave hexagonal honeycomb lattice structure with embedded orthogonal ribs (NAH_C). The compression test results of embedded reinforced impact energy absorption negative Poisson's ratio honeycomb lattice structure with different sine amplitude parameters A are shown in Figure 2. Figure 4 As shown. Figure 4 As can be seen in the figure, with the increase of A, the compression stability of the embedded enhanced impact energy absorption negative Poisson's ratio honeycomb lattice structure is significantly improved, the buckling vibration mode can induce deformation, and the negative Poisson's ratio deformation of the sinusoidal chiral structure 12 can be coupled with the deformation of the concave hexagonal unit cell structure 11, thereby achieving stable compression and shrinkage deformation. The stress-strain test results of the three honeycomb lattice structures are shown in Figure 2. Figure 5 As shown. Figure 5 It can be seen that NAH_T has the lowest stress level, so its bearing capacity and energy absorption capacity are relatively weak. NAH_C has an obvious initial peak stress, and then a stress drop phenomenon occurs. The embedded enhanced impact energy absorption negative Poisson's ratio honeycomb lattice structure shows different stress-strain patterns. Among them, the structure A=1 (NAH_S1) has a certain initial stress peak and has some characteristics of NAH_C. The structure A=3 (NAH_S3) shows a very flat early stage. After the strain reaches 0.25, an obvious stress enhancement effect begins to appear. The structure A=5 (NAH_S5) shows a J-shaped curve, which has always shown obvious stress enhancement. The specific energy absorption (SEA) results of the three honeycomb lattice structures are shown as follows: Figure 6 Compared with NAH_T, the specific energy absorption of the embedded enhanced impact energy absorption negative Poisson's ratio honeycomb lattice structure has been significantly improved, and the SEA of NAH_S1 is similar to that of NAH_C. Figure 7 The energy absorption efficiency of three honeycomb lattice structures is compared. Figure 7 It can be seen that in most strain ranges, NAH_C has the lowest energy absorption efficiency. NAH_T and NAH_S1 structures have stable energy absorption efficiency, while NAH_S3 and NAH_S5 have significantly enhanced energy absorption efficiency at larger strains. This is due to the stable compression concave enhancement effect. In addition, the initial peak stress of NAH_S3 is very small, so NAH_S3 has the highest energy absorption efficiency.

[0036] The simulation test comparison of three aspects with the concave hexagonal honeycomb lattice structure and the concave hexagonal honeycomb lattice structure with embedded orthogonal ribs verifies that the embedded reinforced impact energy absorption negative Poisson's ratio honeycomb lattice structure of the present invention has the following advantages:

[0037] 1) It can exhibit stable compression deformation and negative Poisson's ratio effect within a large deformation range;

[0038] 2) It has obvious self-contact enhancement effect;

[0039] 3) It has large specific energy absorption and high energy absorption efficiency;

[0040] 4) Ability to realize multiple adjustable stress-strain curves. Due to the excellent performance of the present invention, it has great application potential in protective engineering.

[0041] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, article, or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, article, or device comprising the element.

[0042] The embodiments of the present invention are described above in conjunction with the accompanying drawings. What is disclosed is only a preferred embodiment of the present invention. However, the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms and equivalent changes without departing from the scope of protection of the purpose of the present invention and the claims, which are all within the protection of the present invention.

Claims

1. An embedded enhanced impact energy absorbing negative Poisson's ratio honeycomb lattice structure, characterized in that: The embedded reinforced impact energy absorption negative Poisson's ratio honeycomb lattice structure includes N embedded reinforced unit cell structures, the embedded reinforced unit cell structure includes a concave hexagonal unit cell structure and a sinusoidal structure, the sinusoidal structure is embedded in the concave hexagonal unit cell structure, and the embedded reinforced impact energy absorption negative Poisson's ratio honeycomb lattice structure is formed by a periodic array of the embedded reinforced unit cell structures.

2. The embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure according to claim 1, characterized in that: The embedded reinforced unit cell structure includes a plurality of embedded reinforced unit cell structures, and the plurality of embedded reinforced unit cell structures are connected to each other by sharing the rods of the embedded reinforced unit cell structure.

3. The embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure according to claim 1, characterized in that: The embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure is composed of any m×n embedded reinforced unit cell structures; wherein m and n are both positive integers.

4. The embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure according to claim 1, characterized in that: The parameters of the concave hexagonal unit cell structure include the thickness t of the rod, the distance h1 of the concave position in the x-axis direction, the length h2 in the y-axis direction, the height b in the z-axis direction, and the angle θ1; The equation of the sinusoidal structure is: y=Asin(2Πx / h1) in the x-axis direction, x=Asin(2Πy / h2) in the y-axis direction, where the sinusoidal amplitude parameter is A.

5. The embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure according to claim 4, characterized in that: Said A=1.

6. The embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure according to claim 4, characterized in that: Said A=3.

7. The embedded reinforced impact energy absorbing negative Poisson's ratio honeycomb lattice structure according to claim 4, characterized in that: Said A=5.

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